ABOUT THE INFLUENCE OF A PARTIAL TERMINATION OF THE DEFORMATION COMPRESSED ELASTOMERS AT THEIR RESTORING FORCE

If there is a relatively small decrease of an initial constant compres sion of an elastomer sealing during its practical use, a considerable drop of its counterforce resp. sealing ability can follow During a lon g-term test at 23, 70 and 100-degrees-C on six vulcanizates and one th ermoplastic elastomer, the extent of the one stress relaxation was det ermined which is caused by a certain decrease of the initial deformati on besides the viscoelastic and ageing processes in the elastomer Meas ured stress relaxation data of this kind were compared with test resul ts of the stress relaxation test according to DIN 53 537 (method B). P arallel to stress relaxation measurements the compression set was dete rmined. However, in contrast to the usual method, the heated and defor med test pieces were cooled down in the compression apparatus to room temperature before the deformation was removed.